Placenta previa-accreta: risk factors and complications

Development and validation of a nomogram for predicting placenta accreta spectrum in pregnancies with one previous cesarean delivery

OBJECTIVE

This study aimed to develop and validate a prenatal nomogram to predict the risk of placenta accreta spectrum (PAS) in women with one previous cesarean delivery.

METHODS

This retrospective study enrolled 5157 pregnant women with one previous cesarean delivery in China from January 2021 to January 2023. The nomogram was developed from a training cohort of 3612 pregnant women and tested on a validation cohort of 1545 pregnant women. Multivariate regression analysis was performed using the minimum value of the Akaike information criterion to select prognostic factors that can be included in the nomogram. We evaluated the nomogram by the area under the receiver operating characteristic (ROC) curve, calibration curves, and the decision curve analysis (DCA).

RESULTS

PAS occurred in 199 (5.51%) and 80 (5.18%) patients in the training and validation cohorts, respectively. Backward stepwise algorithms in the multivariable logistic regression model determined abortion, hypertensive disorders complicating pregnancy, fetal position, and placenta previa as relevant PAS predictors. The area under the ROC curve for the nomogram was 0.770 (95% confidence interval [CI] 0.733-0.807) and 0.791 (95% CI 0.730-0.853) for the training and validation cohorts, respectively. The calibration curves indicated that the nomogram's prediction probability was consistent with the actual probability. The DCA curve revealed that the nomogram has potential clinical benefit.

CONCLUSION

A prenatal nomogram was developed for PAS in our study, which helped obstetricians determine potential patients with PAS and make sufficient preoperative preparation to reduce maternal and neonatal complications.

Placenta Invasion Anomaly without Placenta Previa in the First Trimester of Pregnancy and its Conservative Management: A Case Presentation

Diagnosing placenta accreta spectrum (PAS) is rather difficult in the first trimester of pregnancy. Especially if the localization of the placenta is not in and around the cervical canal, this may not attract the attention of obstetricians. Early diagnosis can decrease bleeding during curettage or miscarriage, but there are no guidelines regarding its diagnosis in the first trimester. In addition, there is insufficient evidence-based knowledge in the literature on the management and treatment of PAS without placenta previa. In this article, conservative treatment without hysterectomy of a patient diagnosed with PAS in first trimester was presented.

A Retrospective Study in 12-Year cohort of 216 Parturients with Invasive Placentation in a Tertiary Care Centre in Oman: Clinical Outcomes Indicate Severe Maternal Morbidity

Placenta accreta spectrum (PAS) comprising placenta accreta, increta, and percreta, is 1 of the leading causes of peripartum hemorrhage and accounts for up to 50% of all cesarean hysterectomies (CH). We analyzed the data of 216 parturients with PAS who underwent cesarean delivery (CD) and/or CH. Intraoperative surgical complications were noted in 215 (99.5%). The mean estimated blood loss was 2743 (1790) mL, and 105 parturients (48.6%) lost ≥2500 mL. The patients experienced high rates of severe acute maternal morbidity [162 (75%)], hysterectomy [82 (38%)], large volume blood loss, blood transfusion, peripartum anemia, and prolonged hospital stay.

Psychological flexibility, birth satisfaction and postnatal trauma symptoms in women with abnormally invasive placenta

BACKGROUND

Abnormally Invasive Placenta is an obstetric condition resulting in significant physical complications and shown to increase the likelihood of developing Post Traumatic Stress Disorder. Dissatisfaction with the care experienced increases the likelihood of Post Traumatic Stress Disorder. Psychological flexibility has been shown to reduce the severity of Post Traumatic Stress Disorder, but there is no research regarding either of these in women with Abnormally Invasive Placenta.

AIM

To investigate if there is a relationship between trauma experience in women with a diagnosis of Abnormally Invasive Placenta, psychological flexibility, and birth satisfaction.

METHOD

Using a retrospective questionnaire, 126 participants age range 18-45, comprising the Birth Satisfaction Scale Revised Indicator (BSS-RI), Impact of Events Scale Revised (IES-R) and Acceptance and Action Questionnaire (AAQ-2) was completed. A hierarchical regression assessed the predictive relationship of Psychological Flexibility and Birth Satisfaction on Trauma symptoms.

RESULTS

The relationship between Birth Satisfaction measured using the BSS-RI and likelihood of Post Traumatic Stress Disorder (IES-R) was not supported (r (124) = -.08, p = .36). Results did show that Psychological Flexibility (AAQ-2) correlated with Trauma Score (IES-R) (r (124) = .68, p < .001) in women who had experienced Abnormally Invasive Placenta and explained 45.3% of the variance.

CONCLUSION

The results suggest that Post Traumatic Stress Disorder in those with Abnormally Invasive Placenta is as high as 1 in 2 and can be mediated by psychological flexibility. In turn, this suggests that interventions to increase Psychological Flexibility in those with the diagnosis may reduce trauma symptom severity.Abbreviations: AAQ-2 - Acceptance and Action QuestionnaireAIP - Abnormally Invasive PlacentaBAME - Black Asian or other Minority EthnicitiesBSS-RI Birth Satisfaction Scale Revised IndicatorEPH - EPH Gestosis (Pre eclampsia/Eclampsia)DSM - Diagnostic Statical ManualIES-R - Impact of Events Scale RevisedPAS - Placenta Accreta SpectrumPTSD - Post Traumatic Stress Disorder.

Anaemia and red blood cell transfusion in women with placenta accreta spectrum: an analysis of 38,060 cases

Placenta accreta spectrum (PAS) has become a significant life-threatening issue due to its increased incidence and associated morbidity and mortality. Pregnancy is often associated with states of anaemia, and severe maternal haemorrhage represents a major risk factor for red blood cell (RBC) transfusion. The present study retrospectively analyzed the prevalence of anaemia, transfusion requirements and outcome in women with PAS. Using data from the German Statistical Office pregnant patients with deliveries hospitalized between January 2012 and December 2021 were included. Primary outcome was the prevalence of anemia and administration of RBCs. Secondary outcome were complications in women with PAS who received RBC transfusion. In total 6,493,606 pregnant women were analyzed, of which 38,060 (0.59%) were diagnosed with PAS. The rate of anaemia during pregnancy (60.36 vs. 23.25%; p < 0.0001), postpartum haemorrhage (47.08 vs. 4.41%; p < 0.0001) and RBC transfusion rate (14.68% vs. 0.72%; p < 0.0001) were higher in women with PAS compared to women without PAS. Women with PAS who had bleeding and transfusion experienced significantly more peripartum complications than those who did not. A multiple logistic regression revealed that the probability for RBC transfusion in all pregnant women was positively associated with anaemia (OR 21.96 (95% CI 21.36-22.58)). In women with PAS, RBC transfusion was positively associated with the presence of renal failure (OR 11.27 (95% CI 9.35-13.57)) and congestive heart failure (OR 6.02 (95% CI (5.2-7.07)). Early anaemia management prior to delivery as well as blood conservation strategies are crucial in women diagnosed with PAS.

The Role of Ultrasonography and Magnetic Resonance Imaging in the Diagnosis of the Adherent Placenta: An Observational Study

Introduction Placenta accreta is an important factor responsible for maternal morbidity and mortality and is commonly associated with emergent postpartum hysterectomy. The precise prenatal diagnosis of affected pregnancies allows optimal obstetric management. Ultrasonography (USG) and magnetic resonance imaging (MRI) are the only diagnostic modalities available for the prenatal diagnosis of placenta accreta. Objective This study aims to evaluate the accuracy of USG and MRI in diagnosing adherent placenta. Methods Thirty females with placenta previa or a history of previous cesarean sections were evaluated with USG at 28-30 weeks, followed by MRI. The findings of USG and MRI were compared with the intra-operative findings (gold standard) as determined at surgery and by pathological examination. Results Abnormal bridging vessel (n = 24; 80%) was the most common finding seen on USG, whereas abnormal bulge (n = 22; 73.3%) and heterogenous placenta (n = 21; 70%) were the most common findings seen on MRI. The sensitivity of USG and MRI was in the range of 86.7%-92.9% and 92.9%-100%, respectively, in diagnosing three types of adherent placenta. The positive predictive values (PPV) of USG and MRI were in the range of 86.7%-86.7% and 93.8%-100%, respectively, in diagnosing three types of adherent placenta. The accuracy of USG and MRI was in the range of 86.7%-96.7% and 96.7%-100%, respectively, in diagnosing three types of adherent placenta. Conclusion MRI helps to accurately classify placental invasion according to depth, as can be seen from the results of the present study, where the MRI technique was more accurate in diagnosing three types of adherent placenta.

Features of MR signals of retroplacental basal decidual space and its diagnostic significance

BACKGROUND

With more pregnant women undergoing cesarean section, the number of women with scarring in the uterus undergoing uterine magnetic resonance (MR) examination in the second and third trimesters following a subsequent pregnancy, has increased.

OBJECTIVE

To investigate features of MR signals in retroplacental basal decidual space.

METHODS

The MR imaging data of patients with clinically and pathologically confirmed placenta implantation and complete placental abruption were retrospectively analyzed.

RESULTS

Patients with high-intensity signals in T2-weighted images (T2WI) of the retroplacental basal decidual space did not suffer placenta implantation after delivery, while high-intensity signals in T2WI of the retroplacental basal decidual space was not observed in patients with different degrees of placenta implantation.

CONCLUSION

As the retroplacental basal decidual space is the barrier between the placenta and myometrium, high-intensity signals in T2WI can improve the confidence of MR exclusion diagnostics of placenta implantation, and can be used as exclusion criteria for MR diagnosis of placenta implantation.

Comparison of maternal outcomes and clinical characteristics of prenatally vs nonprenatally diagnosed placenta accreta spectrum: a systematic review and meta-analysis

OBJECTIVE

This study aimed to compare maternal outcomes of prenatally and nonprenatally diagnosed placenta accreta spectrum.

DATA SOURCES

A systematic literature search was performed in PubMed, the Cochrane database, and Web of Science until November 28, 2022.

STUDY ELIGIBILITY CRITERIA

Studies comparing the clinical presentation of prenatally and nonprenatally diagnosed placenta accreta spectrum were included. The primary outcomes were emergent cesarean delivery, hysterectomy, blood loss volume, number of transfused blood product units, urological injury, coagulopathy, reoperation, intensive care unit admission, and maternal death. In addition, the pooled mean values for blood loss volume and the number of transfused blood product units were calculated. The secondary outcomes included maternal age, gestational age at birth, nulliparity, previous cesarean delivery, previous uterine procedure, assisted reproductive technology, placenta increta and percreta, and placenta previa.

METHODS

Study screening was performed after duplicates were identified and removed. The quality of each study and the publication bias were assessed. Forest plots and I2 statistics were calculated for each study outcome for each group. The main analysis was a random-effects analysis.

RESULTS

Overall, 415 abstracts and 157 full-text studies were evaluated. Moreover, 31 studies were analyzed. Prenatally diagnosed placenta accreta spectrum was associated with a significantly lower rate of emergency cesarean delivery (odds ratio, 0.37; 95% confidence interval, 0.21-0.67), higher hysterectomy rate (odds ratio, 1.98; 95% confidence interval, 1.02-3.83), lower blood loss volume (mean difference, -0.65; 95% confidence interval, -1.17 to -0.13), and lower number of transfused red blood cell units (mean difference, -1.96; 95% confidence interval, -3.25 to -0.68) compared with nonprenatally diagnosed placenta accreta spectrum. The pooled mean values for blood loss volume and the number of transfused blood product units tended to be lower in the prenatally diagnosed placenta accreta spectrum groups than in the nonprenatally diagnosed placenta accreta spectrum groups. Nulliparity (odds ratio, 0.14; 95% confidence interval, 0.10-0.20), previous cesarean delivery (odds ratio, 6.81; 95% confidence interval, 4.12-11.25), assisted reproductive technology (odds ratio, 0.19; 95% confidence interval, 0.06-0.61), placenta increta and percreta (odds ratio, 3.97; 95% confidence interval, 2.24-7.03), and placenta previa (odds ratio, 6.81; 95% confidence interval, 4.12-11.25) showed statistical significance. No significant difference was found for the other outcomes.

CONCLUSION

Despite its severity, the positive effect of prenatally diagnosed placenta accreta spectrum on outcomes underscores the necessity of a prenatal diagnosis. In addition, the pooled mean values provide a preoperative preparation guideline.

The association between of placenta previa and congenital abnormalities: a systematic review and network meta-analysis

BACKGROUND

Congenital abnormalities, as one of the fetal complications of placenta previa, may cause health problems or disability of the child throughout life. This study aimed to determine the relationship between placenta previa and congenital abnormalities.

METHODS

Potential articles were retrieved from three electronic databases (PubMed/Medline, Scopus, and Web of Sciences) up to 21 May 2023 without limit of time and language. A random effect model was applied for meta-analysis. The heterogeneity was calculated based on I2 statistic and Cochrane Q-test. All analyses were conducted at the significance level of 0.05 using STATA software, version 14. The quality assessment of the included studies was performed using the improved Newcastle-Ottawa Scale.

RESULTS

In the initial search, 829 articles were retrieved. Finally, according to the inclusion criteria, eight studies were analyzed in the meta-analysis. A significant association was reported between placenta previa and risk of congenital abnormalities based on crude form (OR = 1.81, 95% CI = 1.34 to 2.28) and adjusted studies (OR = 6.38, 95% CI = 1.47 to 11.30). The high heterogeneity was observed among the studies reported based on adjusted and crude form, respectively (I2 = 97.9%, P = 0.000) (I2 = 80.6%, P = 0.000). Therefore, publication bias was not observed among studies. Seven studies of the included studies were of high quality.

CONCLUSION

Our study provides evidence that there is a positive and significant association between placenta previa and congenital malformations, including all structural anomalies, chromosomal defects, and congenital hypothyroidisms. Therefore, monitoring congenital abnormalities in the fetus of a mother with placenta previa is necessary.

Dichorionic diamniotic heterotopic twin gestation with cesarean section scar implantation and placenta increta

Heterotopic cesarean scar pregnancy is an extremely rare form of pregnancy and is defined as an intrauterine pregnancy coexisting with an ectopic pregnancy implanted in the cesarean scar. Cesarean scar ectopic pregnancy can also be a precursor for placenta accreta spectrum, a potentially life-threatening condition in which the placenta is abnormally adherent to the uterine myometrium and possibly adjacent organs. Although cesarean scar ectopic pregnancies are rare, there has been an increase in their incidence due to the rise in cesarean deliveries. We present the case of a 35-year-old patient with a heterotopic pregnancy with ectopic implantation in a cesarean scar and associated placenta increta, as well as the radiologic evaluation of placenta accreta spectrum and subsequent management.

Placenta previa percreta with surrounding organ involvement: a proposal for management

Placenta accreta spectrum encompasses cases where the placenta is morbidly adherent to the myometrium. Placenta percreta, the most severe form of placenta accreta spectrum (grade 3E), occurs when the placenta invades through the myometrium and possibly into surrounding structures next to the uterine corpus. Maternal morbidity of placenta percreta is high, including severe maternal morbidity in 82.1% and mortality in 1.4% in the recent nationwide U.S. statistics. Although cesarean hysterectomy is commonly performed for patients with placenta accreta spectrum, conservative management is becoming more popular because of reduced morbidity in select cases. Treatment of grade 3E disease involving the urinary bladder, uterine cervix, or parametria is surgically complicated due to the location of the invasive placenta deep in the maternal pelvis. Cesarean hysterectomy in this setting has the potential for catastrophic hemorrhage and significant damage to surrounding organs. We propose a step-by-step schema to evaluate cases of grade 3E disease and determine whether immediate hysterectomy or conservative management, including planned delayed hysterectomy, is the most appropriate treatment option. The approach includes evaluation in the antenatal period with ultrasound and magnetic resonance imaging to determine suspicion for placenta previa percreta with surrounding organ involvement, planned cesarean delivery with a multidisciplinary team including experienced pelvic surgeons such as a gynecologic oncologist, intra-operative assessment including gross surgical field exposure and examination, cystoscopy, and consideration of careful intra-operative transvaginal ultrasound to determine the extent of placental invasion into surrounding organs. This evaluation helps decide the safety of primary cesarean hysterectomy. If safely resectable, additional considerations include intra-operative use of uterine artery embolization combined with tranexamic acid injection in cases at high risk for pelvic hemorrhage and ureteral stent placement. Availability of resuscitative endovascular balloon occlusion of the aorta is ideal. If safe resection is concerned, conservative management including planned delayed hysterectomy at around 4 weeks from cesarean delivery in stable patients is recommended.

Placenta Accreta Spectrum Disorders: A National Survey

OBJECTIVES

Describe the current practice of Canadian obstetricians-gynaecologists in managing placenta accreta spectrum (PAS) disorders from suspicion of diagnosis to delivery planning and explore the impact of the latest national practice guidelines on this topic.

METHODS

We distributed a cross-sectional bilingual electronic survey to Canadian obstetricians-gynaecologists in March-April 2021. Demographic data and information on screening, diagnosis, and management were collected using a 39-item questionnaire. The survey was validated and pretested among a sample population. Descriptive statistics were used to present the results.

RESULTS

We received 142 responses. Almost 60% of respondents said they had read the latest Society of Obstetricians and Gynaecologists of Canada clinical practice guideline on PAS disorders, published in July 2019. Nearly 1 in 3 respondents changed their practice following this guideline. Respondents highlighted the importance of 4 key points: (1) limiting travel to thereby remain close to a regional care centre, (2) preoperative anemia optimization, (3) performance of cesarean-hysterectomy leaving the placenta in situ (83%), (4) access via midline laparotomy (65%). Most respondents recognized the importance of perioperative blood loss reduction strategies such as tranexamic acid and perioperative thromboprophylaxis via sequential compression devices and low-molecular-weight heparin until full mobilization.

CONCLUSIONS

This study demonstrates the impact of the Society of Obstetricians and Gynaecologists of Canada's PAS clinical practice guideline on management choices made by Canadian clinicians. Our study highlights the value of a multidisciplinary approach to reducing maternal morbidity in individuals facing surgery for a PAS disorder and the importance of regionalized care that is resourced to provide maternal-fetal medicine and surgical expertise, transfusion medicine, and critical care support.

Focal Placenta Accreta in a Congenitally Malformed Uterus: A Case Report

Placenta accreta is defined as an abnormal trophoblast invasion of part or all of the placenta into the myometrium of the uterine wall. It is a well-known cause of maternal morbidity and mortality. Here, we present a unique case of focal placenta accreta due to a bicornuate uterus and a history of septum resection. We also discuss its management and outcome. The patient underwent a classical cesarean section and reinforcement of the anterior and posterior uterine wall. The patient had a history of surgery for correction of uterine malformation, which may have resulted in an abnormal adherence of the placenta.

Prophylactic uterine artery embolization in first-trimester cervical pregnancy termination with placenta accreta: A case report

The current standard treatment for placenta accreta is a hysterectomy, which carries a significant risk of hemorrhage. Although prophylactic uterine artery embolization (UAE) is established as an effective means of minimizing perioperative bleeding, there are few reports of its use early in pregnancy with invasive placenta. A 45-year-old woman, gravida 6, para 1, at 11 weeks of gestation presented with heavy, painless uterine bleeding and was diagnosed with a spontaneous abortion complicated by cervical pregnancy and placenta accreta. The patient underwent bilateral UAE followed by gravid hysterectomy. This case report encourages prophylactic UAE prior to abdominal hysterectomy in patients with early gestational cervical pregnancy and placenta accreta to minimize blood loss during surgery.

Foley Catheter as a Tourniquet for Hemorrhage Prevention during Peripartum Hysterectomy in Patients with Placenta Accreta Spectrum (PAS)-A Hospital-Based Study

BACKGROUND

Placenta accreta spectrum (PAS) is a clinical entity significantly increasing the risk of a peripartum hemorrhage. Various surgical methods have been described in the literature, which aim to reduce the risk of bleeding, although they often lack reproducibility and have been performed on low numbers of patients. The aim of this study was to evaluate the use of the Foley catheter as a cervical tourniquet during cesarean sections, in patients with PAS.

METHODS

All patients who underwent peripartum hysterectomy due to PAS in a large single-center registry were included in the present analysis. The general demographics and clinical characteristics of all participants, including blood loss, and maternal and fetal outcomes, were collected and analyzed.

RESULTS

Twelve participants were included. The mean blood loss was 1200 ± 760 ml during operation and the mean ± SD procedural duration was 89 ± 17 min. The median (Q1-Q3) length of hospital stay post-procedurally was 5 (4-6) days. None of the patients required subsequent urgent surgical procedures after hysterectomy. The median (Q1-Q3) packed red blood cell units transfused in our cohort was 2 (0-3).

CONCLUSION

Using the Foley catheter as a tourniquet might be an effective method of excessive bleeding prevention in patients with PAS during peripartum hysterectomy.

Expression of sirtuin 2 and 7 in placenta accreta spectrum

OBJECTIVE

This study aimed to investigate the expression levels of sirtuin 2 and sirtuin 7 in the placenta accreta spectrum to reveal their role in its pathogenesis.

METHODS

A total of 30 placenta accreta spectrum, 20 placenta previa, and 30 controls were experienced. The sirtuin 2 and sirtuin 7 expression levels in the placentas of these groups were determined by Western blot. sirtuin 2 and sirtuin 7 serum levels in the maternal and fetal cord blood were examined by enzyme-linked immunosorbent assay.

RESULTS

It was found that sirtuin 7 in placenta accreta spectrum was significantly lower in the placenta compared to the control and placenta previa groups (p<0.05). However, a significant difference was not observed between the sirtuin 2 and sirtuin 7 levels in the maternal and fetal cord serum samples of those three groups (p>0.05).

CONCLUSION

Sirtuin 7 may play an important role in the formation of placenta accreta spectrum. The effect of decreased expression of sirtuin 7 might be tissue-dependent in the placenta accreta spectrum and needs to be investigated further.

Pathologically diagnosed placenta accreta spectrum without placenta previa: a systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis aimed to assess clinical characteristics related to pathologically proven placenta accreta spectrum without placenta previa.

DATA SOURCES

A literature search of PubMed, the Cochrane database, and Web of Science was performed from inception to September 7, 2022.

STUDY ELIGIBILITY CRITERIA

The primary outcomes were invasive placenta (including increta or percreta), blood loss, hysterectomy, and antenatal diagnosis. In addition, maternal age, assisted reproductive technology, previous cesarean delivery, and previous uterine procedures were investigated as potential risk factors. The inclusion criteria were studies evaluating the clinical presentation of pathologically diagnosed PAS without placenta previa.

METHODS

Study screening was conducted after duplicates were identified and removed. The quality of each study and the publication bias were assessed. Forest plots and I2 statistics were calculated for each study outcome for each group. The main analysis was a random-effects analysis.

RESULTS

Among 2598 studies that were initially retrieved, 5 were included in the review. With the exception of 1 study, 4 studies were included in the meta-analysis. This meta-analysis showed that placenta accreta spectrum without placenta previa was associated with less risk of invasive placenta (odds ratio, 0.24; 95% confidence interval, 0.16-0.37), blood loss (mean difference, -1.19; 95% confidence interval, -2.09 to -0.28) and hysterectomy (odds ratio, 0.11; 95% confidence interval, 0.02-0.53), and more difficult to diagnose prenatally (odds ratio, 0.13; 95% confidence interval, 0.04-0.45) than placenta accreta spectrum with placenta previa. In addition, assisted reproductive technology and a previous uterine procedure were strong risk factors for placenta accreta spectrum without placenta previa, whhereas previous cesarean delivery was a strong risk factor for placenta accreta spectrum with placenta previa.

CONCLUSION

The differences in clinical aspects of placenta accreta spectrum with and without placenta previa need to be understood.

Knowledge Gaps in Placenta Accreta Spectrum

Since its first description early in the 20th Century, placenta accreta and its variants have changed substantially in incidence, risk factor profile, clinical presentation, diagnosis and management. While systematic use of diagnostic tools and a multidisciplinary team care approach has begun to improve patient outcomes, the condition's pathophysiology, epidemiology, and best practices for diagnosis and management remain poorly understood. The use of large databases with broadly accepted terminology and diagnostic criteria should accelerate research in this area. Future work should focus on non-traditional phenotypes, such as those without placenta previa-preventive strategies, and long term medical and emotional support for patients facing this diagnosis. KEY POINTS: · Placenta accreta spectrum research may be improved with standardized terminology and use of large databases.. · Placenta accreta prediction should move beyond ultrasound with the addition of biomarkers, and needs to extend to those without traditional risk factors.. · Future research should identify practices that can prevent future accreta development..

Placenta Accreta Spectrum and Postpartum Hemorrhage

Placenta accreta spectrum is a group of disorders involving abnormal trophoblastic invasion to the deep layers of endometrium and myometrium. Placenta accrete spectrum is one of the major causes of severe maternal morbidity, with increasing incidence in the past decade mainly secondary to an increase in cesarean deliveries. Severity varies depending on the depth of invasion, with the most severe form, known as percreta, invading uterine serosa or surrounding pelvic organs. Diagnosis is usually achieved by ultrasound, and MRI is sometimes used to assess invasion. Management usually involves a hysterectomy at the time of delivery. Other strategies include delayed hysterectomy or expectant management.

Diagnostic accuracy of ultrasound in the diagnosis of Placenta accreta spectrum: systematic review and meta-analysis

OBJECTIVE

To evaluate the diagnostic accuracy of ultrasound and in the diagnosis of Placenta accreta spectrum (PAS).

DATA SOURCES

Screening of MEDLINE, CENTRAL, other bases from inception to February 2022 using the keywords related to placenta accreta, increta, percreta, morbidly adherent placenta, and preoperative ultrasound diagnosis.

STUDY ELIGIBILITY CRITERIA

All available studies- whether were prospective or retrospective- including cohort, case control and cross sectional that involved prenatal diagnosis of PAS using 2D or 3D ultrasound with subsequent pathological confirmation postnatal were included. Fifty-four studies included 5307 women fulfilled the inclusion criteria, PAS was confirmed in 2025 of them.

STUDY APPRAISAL AND SYNTHESIS METHODS

Extracted data included settings of the study, study type, sample size, participants characteristics and their inclusion and exclusion criteria, Type and site of placenta previa, Type and timing of imaging technique (2D, and 3D), severity of PAS, sensitivity and specificity of individual ultrasound criteria and overall sensitivity and specificity.

RESULTS

The overall sensitivity was 0.8703, specificity was 0.8634 with -0.2348 negative correlation between them. The estimate of Odd ratio, negative likelihood ratio and positive likelihood ratio were 34.225, 0.155 and 4.990 respectively. The overall estimates of loss of retroplacental clear zone sensitivity and specificity were 0.820 and 0.898 respectively with 0.129 negative correlation. The overall estimates of myometrial thinning, loss of retroplacental clear zone, the presence of bridging vessels, placental lacunae, bladder wall interruption, exophytic mass, and uterovesical hypervascularity sensitivities were 0.763, 0.780, 0.659, 0.785, 0.455, 0.218 and 0.513 while specificities were 0.890, 0.884, 0.928, 0.809, 0.975, 0.865 and 0.994 respectively.

CONCLUSIONS

The accuracy of ultrasound in diagnosis of PAS among women with low lying or placenta previa with previous cesarean section scars is high and recommended in all suspected cases.

TRIAL REGISTRATION

Number CRD42021267501.

Animal models of the placenta accreta spectrum: current status and further perspectives

Placenta accreta spectrum disorder (PAS) is a kind of disease of placentation defined as abnormal trophoblast invasion of part or all of the placenta into the myometrium, even penetrating the uterus. Decidual deficiency, abnormal vascular remodeling in the maternal-fetal interface, and excessive invasion by extravillous trophoblast (EVT) cells contribute to its onset. However, the mechanisms and signaling pathways underlying such phenotypes are not fully understood, partly due to the lack of suitable experimental animal models. Appropriate animal models will facilitate the comprehensive and systematic elucidation of the pathogenesis of PAS. Due to the remarkably similar functional placental villous units and hemochorial placentation to humans, the current animal models of PAS are based on mice. There are various mouse models induced by uterine surgery to simulate different phenotypes of PAS, such as excessive invasion of EVT or immune disturbance at the maternal-fetal interface, which could define the pathological mechanism of PAS from the perspective of the "soil." Additionally, genetically modified mouse models could be used to study PAS, which is helpful to exploring the pathogenesis of PAS from the perspectives of both "soil" and "seed," respectively. This review details early placental development in mice, with a focus on the approaches of PAS modeling. Additionally, the strengths, limitations and the applicability of each strategy and further perspectives are summarized to provide the theoretical foundation for researchers to select appropriate animal models for various research purposes. This will help better determine the pathogenesis of PAS and even promote possible therapy.

Engaging pregnant individuals and healthcare professionals in an international mixed methods study to develop a core outcome set for studies on placenta accreta spectrum disorder (COPAS): a study protocol

INTRODUCTION

Placenta accreta spectrum (PAS) disorder is a life-threatening condition that may result in serious maternal complications, including mortality. The placenta which is pathologically adherent to the uterine wall, places individuals at high risk of major haemorrhage during the third stage of labour. Current research reports on PAS disorder outcomes have highly variable levels of information, which is therefore difficult for investigators to aggregate to inform practice. There is an urgent need to harmonise data collection in prospective studies to identify and implement best practices for management. One approach to standardise outcomes across any health area via the use of core outcome sets (COSs), which are consensus-derived standardised sets of outcomes that all studies for a particular condition should measure and report. This protocol outlines the steps for developing a COS for PAS disorder (COPAS).

METHODS AND ANALYSIS

This protocol outlines steps for the creation of COPAS. The first step, a systematic review, will identify all reported outcomes in the scientific literature. The second step will use qualitative one-on-one interviews to identify additional outcomes identified as important by patients and healthcare professionals that are not reported in the published literature. Outcomes from the first two steps will be combined to form an outcome inventory. This outcome inventory will inform the third step which is a Delphi survey that encourages agreement between patients and healthcare professionals on which outcomes are most important for inclusion in the COS. The fourth step, a consensus group meeting of representative participants, will finalise outcomes for inclusion in the PAS disorder COS.

ETHICS AND DISSEMINATION

This study has obtained Research Ethics Board approval from Sunnybrook Health Sciences Centre (#2338, #1488). We will aim to publish the study findings in an international peer-reviewed OBGYN journal.

REGISTRATION DETAILS

COMET Core Outcome Set Registration: https://www.comet-initiative.org/Studies/Details/1127.

PROSPERO REGISTRATION NUMBER

CRD42020173426.

Incidence and Clinical Implications of Placenta Accreta Spectrum after Treatment for Asherman Syndrome

STUDY OBJECTIVE

To investigate the incidence, predictors, and clinical implications of placenta accreta spectrum (PAS) in pregnancies after hysteroscopic treatment for Asherman syndrome (AS).

DESIGN

This is a retrospective cohort study, conducted through a telephone survey and chart review.

SETTING

Minimally invasive gynecologic surgery center in an academic community hospital.

PATIENTS

Database of 355 patients hysteroscopically treated for AS over 4 years. We identified patients who achieved pregnancy past the first trimester and evaluated the incidence and predictors for PAS as well as associated clinical implications.

INTERVENTIONS

Telephone survey.

MEASUREMENTS AND MAIN RESULTS

We identified 97 patients meeting the inclusion criteria. Among these patients, 23 (23.7%) patients had PAS. History of cesarean delivery was the only variable statistically significantly associated with having PAS (adjusted odds ratio 4.03, 95% confidence interval 1.31-12.39). PAS was diagnosed antenatally in 3 patients (14.3%), with patients having placenta previa more likely to be diagnosed (p <.01). Nine patients (39.13%) with PAS required cesarean hysterectomy, which is 9.3% of those with a pregnancy that progressed past the first trimester. Factors associated with cesarean hysterectomy were the etiology of AS (dilation and evacuation after the second trimester pregnancy or postpartum instrumentation, p <.01), invasive placenta (increta or percreta, p <.05), and history of morbidly adherent placenta in previous pregnancies (p <.05). Two patients with PAS (9.5%) had uterine rupture, and another 2 (9.5%) experienced uterine inversion.

CONCLUSION

There is a high incidence of PAS and associated morbidity in pregnancies after hysteroscopic treatment for AS. There is a low rate of antenatal diagnosis as well as a lack of reliable clinical predictors, which both stress the importance of clinical awareness, careful counseling, and delivery planning.

Repeat uterine artery embolization (UAE) for recurrent postpartum hemorrhage in patients who underwent UAE after a previous delivery: a multicenter study

OBJECTIVE

To evaluate angiographic findings and outcomes of repeat uterine artery embolization (UAE) for recurrent postpartum hemorrhage (PPH) in patients who previously underwent UAE for PPH after a previous delivery.

MATERIALS AND METHODS

Among 1805 patients who underwent UAE for PPH from 2007 to 2020 at four participating hospitals, the data of 21 (1.16%) patients who underwent UAE for PPH after subsequent delivery were collected and analyzed retrospectively. The rate of placental abnormalities, causes of PPH, angiographic findings, and clinical success rate were evaluated.

RESULTS

The technical success rates were 100% and 95.2%, and clinical success rates were 85.7% and 95.2% in association with first and second UAEs, respectively. The time intervals between first and second UAEs ranged from 15.6 to 103.3 months (46.5 ± 25.0 months). The rate of placental abnormalities was significantly higher in association with second UAEs than with first UAEs (71.4% vs. 42.8%, p = 0.034). The causes of PPH were different between first and second UAEs with borderline significance (p = 0.049); uterine atony (81.0%) and placenta accreta spectrum (57.1%) were most common in association with first and second UAEs, respectively. During second UAEs, obliterated arteries were observed in 27 uterine arteries (27/42, 64.3%) of 16 patients (16/21, 76.2%), with partial obliteration predominating over total obliteration. Collateral arteries were observed in 15 patients during second UAEs.

CONCLUSION

Repeat UAE is safe and effective for recurrent PPH after subsequent delivery in patients with prior UAE. Obliteration of UAs and formation of collateral arteries are common at the second UAEs.

KEY POINTS

• The rate of placental abnormalities was significantly higher in association with second UAEs than with first UAEs (71.4% vs. 42.8%, p = 0.034). • Obliteration of UAs and formation of collateral arteries are common at the second UAEs. • Repeat UAE is safe and effective for recurrent PPH after subsequent delivery in patients with prior UAE.

Staged treatment of placenta accreta spectrum: A combined surgical and radiological approach

BACKGROUND

Placenta accreta spectrum (PAS) is a rare but serious complication of pregnancy.

AIMS

The aim of this study was to determine maternal and neonatal outcomes following a combined surgical and interventional radiology (IR) approach to managing PAS, and the risks associated with this technique.

METHODS AND MATERIALS

Retrospective cohort study of all cases of PAS in a tertiary maternity centre between January 2001 and July 2020. Women who underwent caesarean hysterectomy for histologically confirmed PAS with a staged surgical and IR approach were compared with those who underwent caesarean hysterectomy without IR. Maternal, neonatal outcomes, surgical and radiological complications were assessed.

RESULTS

Forty-six women were included in the study, and 30/46 (65.2%) underwent the staged surgical and IR approach. Women in the staged group had less overall blood loss (1794 mL vs 3713 mL; P < 0.001), less requirement for blood transfusion (40% vs 75%; P < 0.001), and a lower mean volume of packed red cells transfused (2.5 vs 6.1 units). Anaesthetic and operative times were longer for the staged group (468 vs 189 min: 272 vs 141 min P < 0.001), respectively. There were no differences in rates of neonatal or maternal complications between the two groups.

CONCLUSION

This study demonstrates that a staged procedure combining surgery and IR for PAS results in a considerable reduction in blood loss, need for transfusion, and units of packed red cells transfused compared with surgery alone. The staged procedure required significantly longer anaesthetic and operative times; however, there were no differences in maternal and neonatal morbidity.

Retained Morbidly Adherent Placenta Presenting as a Myometrial Mass in Patients With Vaginal Bleeding: A Case Series and Review of Current Literature

ABSTRACT

The differential diagnosis for a uterine mass and vaginal bleeding after abortion or delivery is broad and includes both benign and malignant causes. A rare etiology for this condition is retained morbidly adherent placenta. Few cases of retained morbidly adherent placenta presenting as a myometrial mass in the setting of vaginal bleeding have been described in the medical literature. In this case series and review of the current literature, we describe the ultrasound features of 3 retained morbidly adherent placentae, along with correlative magnetic resonance imaging findings.

Correlation of placental thickness and placenta percreta in patients with placenta previa: findings from MRI

INTRODUCTION

This study aimed to identify if placental thickness measured from MRI images correlated with placenta percreta in patients with placenta previa.

METHODS

Placental thickness was retrospectively measured in 161 patients from July 2018 to August 2020. The measurements were performed at the thickest part of the placenta in the lower uterine segment on the mid-sagittal plane MR images by two independent radiologists. Intraoperative and pathologic findings were the standard of reference. Univariate and multivariate analyses were performed to identify the relationship between clinical features, placental thickness, and placenta percreta. The predictive ability of placental thickness was demonstrated using receiver operating characteristic curve analysis.

RESULTS

Placental thickness in patients with placenta percreta was significantly higher than in patients with placenta increta, placenta accreta, and normal placentas (p < 0.05). Multivariate analysis revealed that placental thickness was the only independent risk factor for placenta percreta. The cutoff value of placental thickness was 4.35 cm for differentiating placenta percreta in patients with placenta previa.

DISCUSSION

Patients with placenta percreta had the highest placental thickness. Placental thickness was correlated with placenta percreta.

Accuracy of Magnetic Resonance Imaging in Diagnosing Placenta Accreta: A Systematic Review and Meta-Analysis

Background

The disease burden and incidence of placenta accreta are increasing worldwide. The morbidity and mortality associated with undiagnosed placenta accreta are both high, highlighting the important of early diagnosis and intervention. In recent years, increasing studies are exploring the diagnostic value of magnetic resonance imaging (MRI) for placenta accreta. Compared with traditional ultrasound, MRI has the advantages of high-resolution, multiangle imaging, and less influence by amniotic fluid and intestinal gas. However, the reported diagnostic accuracy among studies was inconsistent. Therefore, this study is aimed at exploring the diagnostic value of MRI for placenta accreta by systematic review and meta-analysis.

Methods

Relevant literature were systematically searched in PubMed, Ovid, Embase, ScienceDirect database, CNKI, and Wanfang database by using medical subject headings and relevant diagnostic terminologies such as sensitivity, specificity, likelihood ratio, receiver-operating characteristic curve, and area under the curve. The sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and area under the curve of the included literature were analyzed using stata 17.0 software. Publication bias of the included studies was assessed by Deek's funnel plot. Cochrane Q statistics and I² statistics were used to test the heterogeneity.

Results

A total of 10 primary publications, comprising 4 retrospective studies and 6 prospective studies, were included in this meta-analysis. The gestational weeks of pregnant women ranged from 32 to 35 weeks, and the sample size ranged from 37 cases to 575 cases. Only 4 studies used the blind method in the process of clinical diagnosis by MRI. The combined sensitivity, specificity, and area of curve under summary receiver-operating characteristic for the diagnosis of placenta accreta by MRI were 0.88 (95% CI, 0.79-0.93), 0.79 (95% CI, 0.68-0.87), and 0.91 (95% CI, 0.88.-0.93), respectively. The combined positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and diagnostic score were 4.17 (95% CI, 2.62-6.66), 0.16 (95% CI, 0.09-0.29), 26.61 (95% CI, 10.22-69.28), and 3.28 (95% CI, 2.32-4.24), respectively. No publication bias was noted.

Conclusion

Diagnosis of placenta accreta by MRI has good accuracy and predictive value that warrants clinical promotion.

Three categories of similarities between the placenta and cancer that can aid cancer treatment: Cells, the microenvironment, and metabolites

Cancer is one of the most harmful diseases, while pregnancy is a common condition of females. Placenta is the most important organ for fetal growth, which has not been fully understand. It’s well known that placenta and solid tumor have some similar biological behaviors. What’s more, decidua, the microenvironment of placenta, and metabolism all undergo adaptive shift for healthy pregnancy. Interestingly, decidua and the tumor microenvironment (TME); metabolism changes during pregnancy and cancer cachexia all have underlying links. However, whether the close link between pregnancy and cancer can bring some new ideas to treat cancer is still unclear. So, in this review we note that pregnancy may offer clues to treat cancer related to three categories: from cell perspective, through the shared development process of the placenta and cancer; from microenvironment perspective, though the shared features of the decidua and TME; and from metabolism perspective, through shared metabolites changes during pregnancy and cancer cachexia. Firstly, comparing gene mutations of both placenta and cancer, which is the underlying mechanism of many similar biological behaviors, helps us understand the origin of cancer and find the key factors to restore tumorigenesis. Secondly, exploring how decidua affect placenta development and similarities of decidua and TME is helpful to reshape TME, then to inhibit cancer. Thirdly, we also illustrate the possibility that the altered metabolites during pregnancy may reverse cancer cachexia. So, some key molecules changed in circulation of pregnancy may help relieve cachexia and make survival with cancer realized.

Maternal Smoking and the Risk of Placenta Accreta Spectrum: A Systematic Review and Meta-Analysis

Background

This is the first meta-analysis that assessed the association between maternal smoking and the risk of placenta accreta spectrum (PAS), so this study was aimed at investigating the association between maternal smoking and PAS based on observational studies. PAS is defined as a severe obstetric complication due to the abnormal invasion of the chorionic villi into the myometrium and uterine serosa.

Methods

We searched electronic bibliographic databases including PubMed, Web of Science, Scopus, Science Direct, and Google Scholar until January 2022. The results were reported using a random effect model. The chi-square test and the I² statistic were used to assess heterogeneity. Egger's and Begg's tests were used to examine the probability of publication bias. All statistical analyses were performed at a significance level of 0.05 using Stata software, version 11.

Results

Based on the random effect model, the estimated OR of the risk of PAS associated with smoking was 1.21 (95% CI: 1.02, 1.41; I² = 4.7%). Subgroup analysis was conducted based on study design, and the result showed that the association between smoking and PAS among cohort studies was significant 1.35 (95% CI: 1.15, 1.55; I² = 0.0%).

Conclusion

Our results suggested that maternal smoking is a risk factor for the PAS. There was no heterogeneity among studies that reported an association between smoking and the PAS. The Newcastle-Ottawa Scale (NOS) was used to measure study quality.

The MRI estimations of placental thickness and cervical length correlate with postpartum hemorrhage (PPH) in patients with risk for placenta accreta spectrum (PAS) disorders

INTRODUCTION

This study aims to identify whether placental thickness and cervical length measured by MRI correlate with postpartum hemorrhage (PPH) in patients at high risk for placenta accreta spectrum (PAS) disorders.

METHODS

The placental thickness and cervical length of 200 patients from October 2017 to October 2021 were retrospectively measured. The mid-sagittal plane of the placentas was measured by 2 independent radiologists using MRI. Partial correlation analysis was used to characterize the correlation between placental thickness, cervical length and estimated blood loss during surgery. The correlation between clinical features, placental thickness, cervical length and PPH was evaluated with univariate and multivariate analyses. A nomogram was constructed based on the logistic regression.

RESULTS

Placental thickness was positively correlated with the estimated blood loss during delivery, while cervical length had a negative correlation with it, based on the adjustment for gestational age. Multivariate analyses revealed that prior cesarean section, placenta previa, increased placental thickness(≧4.35 cm) and short cervical length（< 3.05 cm） were independent risk factors for PPH. When the 4 risk factors were combined together, the AUC was the highest, 0.773 (95%CI 0.707-0.840).

DISCUSSION

Placental thickness and cervical length correlated with PPH. The nomogram constructed based on prior cesarean section, placenta previa, placental thickness and cervical length can be used to recognize patients with a higher risk of PPH.

Bleeding-related outcomes of low-risk total placenta previa are equivalent to those of partial/marginal placenta previa

OBJECTIVE

To clarify whether "low-risk total PP" patients bleed more than partial/marginal PP patients.

MATERIALS AND METHODS

The retrospective cohort study was performed involving patients with PP between April 2006 and December 2018. The placental position was determined by ultrasound. From medical charts, the backgrounds as well as obstetric and neonatal outcomes of PP patients were retrieved.

RESULTS

This study included 349 patients with PP, which was classified into three types according to the distance between the placenta and internal ostium: total (n = 174), partial (n = 52), and marginal (n = 123) PP. In total PP patients, three factors (prior CS, anterior placenta, and placental lacunae on ultrasound) significantly increased blood loss at CS, the need for hysterectomy, homologous transfusion (≥10 U), and ICU admission. No significant difference was observed in bleeding-related poor outcomes (rate of blood loss ≥2000 mL, amount of homologous transfusion, need for hysterectomy, and ICU admission) between total PP patients without all three factors: "low-risk total PP patients" and partial/marginal PP patients (19.8 vs. 17.1%; p = 0.604, 3.7 vs. 1.1%; p = 0.330, 1.2 vs. 1.1%; p = 1.000, and 1.2 vs. 1.1%; p = 1.000, respectively).

CONCLUSION

Prior CS, anterior placenta, and placental lacunae on ultrasound were risk factors for a bleeding-related poor outcome in total PP patients. Total PP patients without these three factors showed the same bleeding-related poor outcome as partial/marginal PP patients.

Placenta Accreta has a Low Association with Hypertensive Disease During Pregnancy: A Systematic Review Incorporating a Network Meta-analysis

A meta-analysis was performed to evaluate the potential relationship between hypertensive disease during pregnancy and placenta accreta. A systematic literature search in OVID, Embase, Cochrane Library, PubMed, and Google scholar up to May 2021 was done, and 4 studies were found including 47,353 pregnant women at the start of the study; 4283 of them had hypertensive disease during pregnancy and 493 had placenta accreta. They were reporting relationships between hypertensive disease during pregnancy and placenta accreta. The odds ratio (OR) with 95% confidence intervals (CIs) was calculated to assess the potential relationship between hypertensive disease during pregnancy and placenta accreta using the dichotomous with a random or fixed-effect model. Hypertensive disease during pregnancy was significantly related to lower prevalence of placenta accreta (OR, 0.60; 95% CI, .38-.94, p = 0.03) compared with control (no hypertensive disease during pregnancy). When looking at the result comparing the prevalence of hypertensive disease during pregnancy in women with placenta accreta compared with control (no placenta accreta), we found that the placenta accreta was significantly related to lower prevalence of hypertensive disease during pregnancy (OR, 0.59; 95% CI, 0.38-0.94, p = 0.03) compared with control. Hypertensive disease during pregnancy may have a lower prevalence of placenta accreta. Further studies are required to validate these findings.

Retained Placenta and Postpartum Hemorrhage: A Case Report and Review of Literature

The third stage of labor (delivery of the placenta), per current definition, takes place within 30 minutes of fetal delivery in a nulliparous or multiparous woman. According to the American Pregnancy Association, a retained placenta is diagnosed if the placenta is not delivered within 30 minutes following delivery of the fetus. Retained placenta can be caused by placenta accreta, increta, or percreta. There are several complications of a retained placenta, including postpartum hemorrhage, which can lead to maternal death if not treated promptly. We report the case of a 32-year-old female, gravida 4 para 3, who was diagnosed with a retained placenta after delivering at term (39 weeks gestation). The retained placenta was complicated by postpartum hemorrhage and was treated within 15 minutes of fetal delivery with several uterotonics (misoprostol, oxytocin, carboprost, and tranexamic acid) and several passes of ultrasound-guided suction curettage. Sharp curettage was also used with ultrasound to confirm that the uterus was empty, followed by one more suction curettage to remove any products of conception that were scraped off with sharp curettage. Vaginal bleeding was significantly reduced; minor bleeding was noted from a first-degree vaginal laceration, which was repaired by suture. The patient recovered from surgery and was discharged on postpartum day 3 with her neonate in stable condition. In conclusion, this case highlights that retained placenta is a serious obstetric complication that can cause life-threatening postpartum hemorrhage. More data are needed to define the period of time correlating with the greatest chance of encountering a retained placenta in order to improve obstetric care and reduce maternal morbidity and mortality. Future research should consider challenging the current definition of retained placenta, defined as a placenta undelivered after 30 minutes, in favor of a shorter time period, 15 minutes undelivered, in order to mobilize the obstetric team, anesthesiologist, and blood bank to prevent catastrophic postpartum hemorrhage.

Comparison of One-Stage and Two-Stage Intraoperative Uterine Artery Embolization during Cesarean Delivery for Placenta Accreta: Report of Two Clinical Cases at a Tertiary Referral Medical Center

Placenta accreta spectrum (PAS) described the anchoring placental villi attached or penetrating into/through the myometrium. PAS is clinically important because of the unpredictable bleeding amount when manually removing the defective decidualization at the endometrial-myometrial interface. Therefore, a multidisciplinary strategy for cesarean delivery with PAS is crucial. Postoperative embolization after cesarean hysterectomy in a hybrid suite was studied by many scientists. In this study, we demonstrated two cases of intraoperative embolization without hysterectomy in a hybrid operating room for cesarean delivery with placenta accreta. Our results show that intraoperative uterine artery embolization with a hybrid suite is a time-preserving and safe method for cesarean delivery with PAS owing to avoiding the risk of morbidity and mortality during patient transfer.

Hypertension in pregnancy as a risk factor for placenta accreta spectrum: a systematic review incorporating a network meta-analysis

BACKGROUND

A meta-analysis was performed to evaluate the potential effects of hypertension in pregnancy on the placenta accreta spectrum.

METHODS

A systematic literature search in OVID, Embase, Cochrane Library, PubMed, and Google Scholar up to May 2021 was done, and six studies were found including 126,224 pregnant women; 7164 of them had hypertension in pregnancy and 816 had placenta accreta spectrum. They were reporting relationships between the potential effects of hypertension in pregnancy on the placenta accreta spectrum. The odds ratio (OR) with 95% confidence intervals (CIs) was calculated to assess the potential effects of hypertension in pregnancy on the placenta accreta spectrum using the dichotomous with a random- or fixed-effect model.

RESULTS

Pregnancy-induced hypertension was significantly related to lower prevalence of placenta accreta spectrum (OR 0.56; 95% CI 0.37-0.84, p = 0.005) with no heterogeneity (I² = 0%) compared to control (no hypertension in pregnancy). When looking at the result comparing the prevalence of hypertension in pregnancy in women with placenta accrete compared to control (no placenta accrete), we found that the placenta accreta spectrum was significantly related to lower prevalence of hypertension in pregnancy (OR 0.65; 95% CI 0.43-0.98, p = 0.04) compared to control.

CONCLUSIONS

Hypertension in pregnancy may have a lower prevalence of placenta accrete. Further studies are required to validate these findings.

First-trimester ultrasound diagnostic features of placenta accreta spectrum in low-implantation pregnancy

OBJECTIVE

Low-implantation pregnancy (LIP) is an important marker for the diagnosis of placenta accreta spectrum (PAS) in the first trimester. Many grayscale and color Doppler ultrasound markers of PAS have been defined in the second and third trimesters of pregnancy, but have not been studied in the first trimester. The aim of this study was to determine whether PAS sonographic markers could be used in the first trimester to differentiate patients with LIP who develop PAS from those who do not.

METHODS

This was a retrospective case-control study of women who delivered at our institution between 2009 and 2019. Cases were women with PAS who delivered by Cesarean hysterectomy and who had undergone first-trimester ultrasound demonstrating LIP. Controls were women with persistent placenta previa without PAS who delivered by Cesarean section without postpartum hemorrhage and who had undergone first-trimester ultrasound demonstrating LIP. Sonographic images were reviewed by an investigator blinded to pregnancy outcome and ultrasound reports. Images were reviewed for presence of abnormal uteroplacental interface, increased lower uterine segment hypervascularity and placental lacunae, with or without swirling on grayscale or color Doppler ultrasound.

RESULTS

Following review of the electronic health records, 21 cases and 46 controls met the inclusion criteria. Placental lacunae were present in 18/21 (85.7%) cases and 7/46 (15.2%) controls (odds ratio (OR), 33.4; 95% CI, 7.7-144.4; P < 0.001). The number of lacunae was significantly higher in cases compared with controls, with a median of five lacunae present in cases compared with a median of one lacuna in controls (P < 0.001). The median size of the lacunae was also significantly larger in cases compared with controls, measuring 10.03 (interquartile range (IQR), 7.3-12.05) mm and 4.15 (IQR, 4.05-5.05) mm, respectively (P = 0.001). Lacunae swirling on grayscale or color Doppler ultrasound was noted only in PAS cases, with 10/12 (83.3%) having swirling on grayscale ultrasound and 12/12 (100%) having swirling on color Doppler (P < 0.001). Presence of an abnormal uteroplacental interface was also observed only in PAS cases, at a rate of 17/20 (85.0%) (P < 0.001). Lower uterine segment (uterovesical, subplacental and/or intraplacental) hypervascularity was present in 14/14 (100%) cases and only 1/12 (8.3%) controls (P < 0.001).

CONCLUSION

In women at risk of PAS, ultrasound markers of PAS can and should be assessed as early as in the first trimester. The use of a first-trimester prenatal ultrasound screening protocol and standardized approach to ultrasound examination in at-risk mothers may help increase detection of PAS and enable planning for optimal management of affected pregnancies. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Cervical tourniquet during cesarean section to reduce bleeding in morbidly adherent placenta: a pilot study

Objective:

To evaluate a modified surgical technique aiming to reduce bleeding and preserve fertility in morbidly adherent placenta by cervical tourniquet in cesarean sections.

Methods:

The cesarean section operations and the cervical ligation approach were performed by a single expert consultant obstetrician. The general demographics and clinical characteristics for all participants were collected and studied.

Results:

Eleven participants were involved. The uterus was preserved in nine patients, whereas two patients had hysterectomy. The mean blood loss was 1688.8 ml for patients whose uterus was preserved. The mean length of stay was 5.5 days.

Conclusion:

Cervical ligation is a simple method that can be applied by junior and experienced obstetricians to preserve the uterus.

Placenta accreta is the abnormal adhesion of placenta into the uterine wall. It carries a significant risk for hysterectomy, intrapartum and postpartum hemorrhage, and maternal morbidity and mortality. As the preservation of fertility and femininity is desired by many women, numerous methods were adapted to avoid hysterectomy in patients with placenta accreta. In this study, we describe and evaluate a novel technique to preserve the uterus by ligating the cervix with a Foley catheter.

Pregnancy complications and risk of uterine rupture among women with singleton pregnancies in China

BACKGROUND

The goal of this study was to investigate whether pregnancy complications are associated with an increased risk of uterine rupture (UR) and how that risk changes with gestational age.

METHODS

We obtained all data from China's National Maternal Near Miss Surveillance System (NMNMSS) between 2012 and 2018. Poisson regression analysis was used to assess the risk of UR with pregnancy complications (preeclampsia, gestational diabetes mellitus, placental abruption, placenta previa and placenta percreta) among 9,454,239 pregnant women. Furthermore, we analysed the risks of UR with pregnancy complications in different gestational age groups.

RESULTS

The risk of UR was increased 2.0-fold (1.2-fold to 2.7-fold) in women with pregnancy complications (except for preeclampsia). These associations also persisted in women without a previous caesarean delivery. Moreover, an increased risk of UR before term birth was observed among women with gestational diabetes mellitus, placental abruption and placenta percreta. The risk of UR was slightly higher in women with gestational diabetes mellitus who had a large for gestational age (LGA) foetus, especially at 32 to 36 weeks gestation.

CONCLUSIONS

The risk of UR is associated with gestational diabetes mellitus, placental abruption, placenta previa and placenta percreta, but varies in different gestational ages.

Expectant management of placenta accreta after a mid-trimester pregnancy loss: a case report and a short review

Objectives

Placenta accreta spectrum (PAS) disorders are a significant cause of maternal morbidity and mortality. Traditionally women with PAS are offered surgery, while expectant management is still considered investigational.

Case presentation

We present a case of expectant management of PAS after pregnancy loss at 19-weeks. PAS was suspected at sonography and confirmed by MRI. Patient was offered expectant management to preserve fertility. This consisted of leaving the placenta in situ, followed by in- and out-patient clinical and sonographic examinations and blood tests. After five weeks placental detachment occurred without major complications.

Conclusions

Our report suggests that expectant management could be a safe option in selected cases of PAS after mid-trimester pregnancy loss. We recommend expectant management should be offered in referral centers for PAS.

Potentially Preventable Primary Cesarean Sections in Future Placenta Accreta Spectrum

OBJECTIVE

Prior cesarean delivery is a well-known risk factor for placenta accreta spectrum disorders. While primary cesarean section is unavoidable in some patients, in others it may not be clearly indicated. The aim of the study is to determine the proportion of patients with placenta accreta spectrum who had a potentially preventable primary cesarean section and to identify factors associated with preventable placenta accreta spectrum.

STUDY DESIGN

This was a single-center retrospective cohort study of women with pathology-confirmed placenta accreta spectrum from 2007 to 2019. Primary cesarean sections were categorized as potentially preventable or unpreventable based on practice consistent with the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine "Safe Prevention of the Primary Cesarean Delivery" recommendations. Fisher's exact test and Mann-Whitney U-test were used for comparison with p <0.05 considered statistically significant.

RESULTS

Seventy-two patients had pathology-confirmed placenta accreta spectrum over the course of the study period, 15 (20.8%) of whom required a cesarean hysterectomy at the time of primary cesarean section. Fifty-seven patients had placenta accreta spectrum in a pregnancy following their primary cesarean section. Of these, 29 (50.9%) were considered potentially preventable. Most were performed without clear medical indication (37.9%) or for fetal malpresentation without attempted external cephalic version (37.9%). The remainder were due to arrest of labor not meeting criteria (17.2%) and abnormal or indeterminate fetal heart patterns with documented recovery (6.9%). Of the 11 patients without clear medical indication for primary cesarean section, eight (72.7%) were patient-choice cesarean sections and three (27.3%) were for suspected fetal macrosomia with estimated fetal weights not meeting criteria for cesarean delivery. There was no difference in the incidence of potentially preventable primary cesarean sections before and after the ACOG-SMFM "Safe Prevention of the Primary Cesarean Delivery" publication (48.8 vs. 57.1%, p = 0.59). Privately insured patients were more likely to have a potentially preventable primary cesarean section than those with Medicaid (62.5 vs. 23.5%, p = 0.008) and were more likely to have a primary cesarean section without clear medical indication (81.8 vs. 18.2%, p = 0.004).

CONCLUSION

Many patients with placenta accreta spectrum had a potentially preventable primary cesarean section. Most were performed without clear medical indication or for malpresentation without attempted external cephalic version, suggesting that at least a subset of placenta accreta spectrum cases may be preventable. This was particularly true for privately insured patients. These findings call for continued investigation of potentially preventable primary cesarean sections with initiatives to address concerns at the patient, provider, and hospital level.

KEY POINTS

· Many patients with placenta accreta spectrum have potentially preventable primary cesarean sections.. · Privately insured patients are more likely to have potentially preventable primary cesarean sections.. · Our findings suggest that at least a subset of placenta accreta spectrum cases may be preventable..

Extravillous trophoblast migration and invasion: Impact of environmental chemicals and pharmaceuticals

During pregnancy, the migration and invasion of extravillous trophoblasts (EVTs) into the maternal uterus is essential for proper development of the placenta and fetus. During the first trimester, EVTs engraft and remodel maternal spiral arteries allowing for efficient blood flow and the transfer of essential nutrients and oxygen to the fetus. Aberrant migration of EVTs leading to either shallow or deep invasion into the uterus has been implicated in a number of gestational pathologies including preeclampsia, fetal growth restriction, and placenta accreta spectrum. The migration and invasion of EVTs is well-coordinated to ensure proper placentation. However, recent data point to the ability of xenobiotics to disrupt EVT migration. These xenobiotics include heavy metals, endocrine disrupting chemicals, and organic contaminants and have often been associated with adverse pregnancy outcomes. In most instances, xenobiotics appear to reduce EVT migration; however, there are select examples of enhanced motility after chemical exposure. In this review, we provide an overview of the 1) current experimental approaches used to evaluate EVT migration and invasion in vitro, 2) ability of environmental chemicals and pharmaceuticals to enhance or retard EVT motility, and 3) signaling pathways responsible for altered EVT migration that are sensitive to disruption by xenobiotics.

Clinical and hemodynamic insights into the use of internal iliac artery balloon occlusion as a prophylactic technique for treating postpartum hemorrhage

Recently, the effectiveness of internal iliac artery balloon occlusion (IIABO) for treating postpartum hemorrhage caused by pernicious placenta previa (PPP) has been questioned. We conducted a retrospective analysis and hemodynamic simulation to assess the IIABO's effectiveness. The retrospective analysis involved 480 patients with PPP, among which 288 underwent IIABO treatment and the remaining 192 were used as controls. Blood loss and preoperative indicators were recorded, and multiple regression analysis was applied to test the effect of preoperative indicators on blood loss. Hemorrhage mechanisms were simulated using a numerical model. Results suggested that no significant difference in blood loss (1836 ± 1440 ml vs. 1784 ± 1647 ml, p = 0.22) was observed between the two groups. In addition, preoperative indicators, including age, weight, gestational age, gravidity, parity, blood type, anemia, or diabetes, were not associated with blood loss. In the simulation, after the intra-iliac artery was blocked, blood loss was caused by a reversed flow in the intrapelvic arteries, uterine veins, and uterine venules. The ratio of the time-averaged hemorrhage velocity (TAHV) in the balloon group to that in the control group was lower than that obtained in a clinical study (13.0% vs. 88.9%); in the presence of collateral circulation, blood loss occurred from collateral circulation and uterine venules after IIABO intervention, and the TAHV was 60%-90% that of the control group, which was closer to the clinical results (88.9%). These results suggest that IIABO cannot effectively treat postpartum hemorrhage because of the collateral circulation and reversed flow in the uterine venules.

Placenta Accreta Spectrum

Placenta accreta spectrum (PAS) refers to the range of pathologic adherence of the placenta to the uterine myometrium, including the placenta accreta, increta, and percreta. The incidence of PAS is rising primarily because of an increase in related risk factors, such as the rate of cesarean deliveries and pregnancies resulting from assisted reproductive technology. The maternal risks associated with PAS are significant, including hemorrhage, hysterectomy, and death. Fetal and neonatal risks are primarily the result of premature delivery. Antenatal diagnosis via ultrasonography and magnetic resonance imaging remains imperfect. Management of PAS varies, however, and there is a clear improvement in maternal outcomes with an antenatal diagnosis compared with unexpected diagnosis at the time of delivery. Studies that evaluate the balance between maternal and fetal/neonatal risks of expectant management versus preterm delivery have found that planned delivery between 34 and 35 weeks' gestation optimizes outcomes. Multidisciplinary PAS care teams have become the norm and recommended approach to management, given the complexity of caring for this obstetrical condition. Although significant advances have been made over the years, large knowledge gaps remain in understanding the pathophysiology, diagnosis, and clinical management.

Conservative stepwise surgical approach for management of placenta previa accreta: A prospective case series study

OBJECTIVE

To describe a stepwise surgical approach for conservative management of placenta previa accreta to preserve the uterus and to evaluate the efficacy and safety of this approach in controlling postpartum hemorrhage including intrapartum hemorrhage.

METHODS

A prospective case series study conducted on 62 pregnant women with one or more cesarean deliveries diagnosed with placenta previa accreta between January 2018 and June 2019 at Ain Shams University Maternity Hospital. All participants underwent a conservative stepwise surgical approach through Pfannenstiel skin incision with fetal delivery through a uterine incision just above the upper border of the placenta, followed by bilateral uterine artery ligation with myometrial excision of the remaining adherent placenta and cervico-isthmic sutures by MMG (the main surgeon) and MS.

RESULTS

Among 62 women, the surgical approach was successful in controlling postpartum hemorrhage and preserving the uterus in 50 (80.64%) participants. Three women (4.83%) had urinary bladder injuries, all were managed intraoperatively during the cesarean section. Five women (8%) had postpartum pyrexia and five women (8%) had postpartum endometritis, all were managed conservatively with broad-spectrum antibiotics.

CONCLUSION

The stepwise surgical approach can be applied to the conservative management of placenta previa accreta to avoid unnecessary cesarean hysterectomy.

Development and validation of a magnetic resonance imaging-based nomogram for predicting invasive forms of placental accreta spectrum disorders

AIM

The aim of the study was to develop and validate a magnetic resonance imaging (MRI)-based nomogram for predicting invasive forms of placental accreta spectrum (PAS) disorders (placenta increta and percreta) with "uncertain ultrasound diagnosis."

METHODS

This was a retrospective cohort study of a primary cohort of 118 patients and a validation cohort of 65 patients with "uncertain ultrasound diagnosis," who were further evaluated by MRI. MRI signs associated with PAS disorders were analyzed between invasive and noninvasive groups by both univariate and logistic regression to construct the nomogram. The accuracy and discriminative ability of the nomogram were measured by concordance index (C-index) and calibration curve internally and externally.

RESULTS

The history of previous cesarean deliveries (odds ratio [OR], 3.27; 95% confidence interval [CI], 1.16-9.27), loss of double-line sign (OR, 9.49; 95% CI, 3.06-29.48), abnormal uterine bulging (OR, 4.05; 95% CI, 1.53-10.69), and disorganized abnormal placenta vascularity (OR, 3.38; 95% CI, 1.09-10.50) were imputed for the nomogram. The C-index of the nomogram was 0.85 for internal validation and 0.84 for external validation. Calibration curve showed good agreement with predicted risk and actual observation for both primary and validation cohort.

CONCLUSIONS

MRI can be a useful adjunct for clinical staging of patients with "uncertain ultrasound diagnosis."

Placenta accreta spectrum: Management and outcomes in a tertiary centre in India: An observational cross-sectional study

Our observational cross-sectional study looked at the risk factors, diagnosis, management and outcomes of placenta accrete spectrum at the Christian Medical College and Hospital, Vellore, India, between January 2013 and December 2018. A total of 21 cases of placenta accrete spectrum are described among whom a preop diagnosis was available in 14 cases. A previous history of Caesarean section and placenta previa was present in 90%. Caesarean hysterectomy was carried out in 80%, but none of those managed conservatively required interval hysterectomy. Urinary tract injury was the most common surgical complication, seen in over 50%. The mean blood loss was 3.5 l and 14 patients required intensive care unit admission, but no maternal mortality ensued. Thus, we conclude that the conservative management in carefully selected cases is feasible.

Association between Number of Prior Cesareans and Early Preterm Delivery in Women with Abnormal Placentation

OBJECTIVE

Delivery timing at 34 to 36 weeks is nationally recommended for pregnancies complicated by placenta accreta spectrum (PAS). However, it has recently been suggested that those with ≥2 prior cesarean deliveries (CD) and PAS should be delivered earlier than 34 weeks because of a higher risk of unscheduled delivery and complications. We sought to evaluate whether the number of prior CD in women with PAS is associated with early preterm delivery (PTD) (<34 weeks). We also evaluated the same relationship in women with placenta previa alone (without PAS).

STUDY DESIGN

This is a secondary analysis of a multicenter and observational study that included women with prior CD (maternal-fetal medicine unit cesarean registry). Women with a diagnosis of PAS (regardless of placenta previa) were included for our primary analysis, and women with known placenta previa (without a component of PAS) were independently analyzed in a second analysis. Two groups of patients from the registry were studied: patients with PAS (regardless of placenta previa) and patients with placenta previa without PAS. The exposure of interest was the number of prior CD: ≥2 CD compared with <2 CD. The primary outcome was PTD <34 weeks. Secondary outcomes included preterm labor requiring hospitalization or tocolysis, transfusion of blood products, composites of maternal and neonatal morbidities, and NICU admission. Outcomes by prior CD number groups were compared in both cohorts. Backward selection was used to identify parsimonious logistic regression models.

RESULTS

There were 194 women with PAS, 97 (50%) of whom had <2 prior CD and 97 (50%) of whom had ≥2 prior CD. The rate of PTD <34 weeks in women with ≥2 prior CD compared with <2 in the setting of PAS was 23.7 versus 29.9%, p = 0.27; preterm labor requiring hospitalization was 24.7 versus 13.5%; p = 0.05. The rates of plasma transfusion were increased with ≥2 prior CD (29.9 vs. 17.5%, p = 0.04), but there were no differences in transfusion of other products or in composite maternal or neonatal morbidities. After multivariable adjustments, having ≥2 CDs was not associated with PTD <34 weeks in women with PAS (adjusted odds ratio (aOR): 0.73, 95% confidence interval [CI]: 0.39-13.8) despite an association with preterm labor requiring hospitalization (aOR: 2.69; 95% CI: 1.15-6.32). In our second analysis, there were 687 women with placenta previa, 633 (92%) with <2 prior CD, and 54 (8%) with ≥2 prior CD. The rate of PTD <34 weeks with ≥2 CD in the setting of placenta previa was not significantly increased (27.8 vs. 22.1%, aOR: 1.49; 95% CI: 0.77-2.90, p = 0.08); the maternal composite outcome (aOR: 4.85; 95% CI: 2.43-9.67) and transfusion of blood products (aOR: 6.41; 95% CI: 2.30-17.82) were noted to be higher in the group with ≥2 prior CD.

CONCLUSION

Women with PAS who have had ≥2 prior CD as compared with women with <2 prior CD did not appear to have a higher risk of complications leading to delivery prior to 34 weeks. As such, considering the associated morbidity with early preterm birth, we would not recommend scheduled delivery prior to 34 weeks in this population.

KEY POINTS

· We do not recommend delivery prior to 34 weeks of gestational age in PAS.. · PTD was not significantly increased in PAS with ≥2 CDs.. · PTD < 34 weeks of gestational age was not increased in placenta previa with ≥2 prior CDs..

Postpartum Hemorrhages: Prevention

The strict correlation between abnormal invasive placentation and postpartum hemorrhage suggests that a widespread antenatal diagnosis of placental anomalies would improve the management of these challenging patients; acting preventive solutions at the moment of delivery reduces blood loss and avoid hysterectomies. The role of endovascular procedures in this field has been encouraged by multiple studies reporting prophylactic uterine arteries embolization and iliac/aortic balloon catheters positioning. This paper aims to review the main imaging diagnostic findings of placental implant anomalies and summarize the principal preventive endovascular strategies proposed in literature.